import {baseUrl} from './env';

export default async(url = '', data = {}, type = 'GET', method = 'fetch') => {
    type = type.toUpperCase();
    url = baseUrl + url;

    if( type == 'GET' ) {
        let dataStr = '';//数据拼接字符串
        Object.keys(data).forEach(key => {
            dataStr += key + '=' + data[key] + '&';
        })

        if( dataStr !== '' ) {
            dataStr = dataStr.substr(0, dataStr.lastIndexOf('&'));
            url = url + '?' + dataStr;
        }
    }

    if ( window.fetch && method == 'fetch' ) {
        let requestConfig = {
            credentials: 'include',
            method: type,
            headers: {
                'Accept': 'application/json',
                'Content-Type': 'application/json'
            },
            mode: 'cors',
            cache: 'force-cache'
        }

        if ( type == 'POST' ) {
            Object.defineProperty(requestConfig, 'body', {
                value: JSON.stringify(data)
            })
        }

        try {
            const response = await fetch(url, requestConfig);
            const responseJson = await response.json();
            return responseJson
        } catch (error) {
            throw new Error(error)
        }
    }else {
       return new Promise((resolve, reject) => {
           let requestObj;
           if( window.XMLHttpRequest ) {
               requestObj = new XMLHttpRequest();
           }else {
               requestObj = new ActiveXObject;
           }

           let sendData = '';
           if ( type == 'POST' ) {
               sendData = JSON.stringify(data);
           }

           requestObj.open(type, url, true);
           requestObj.setRequestHeader('Content-type','application/x-www-form-urlencoded');
           requestObj.send(sendData);

           requestObj.onreadystatechange = () => {
               if ( requestObj.readyState == 4 ) {
                   if ( requestObj.status == 200 ) {
                      let obj = requestObj.response
                      if ( typeof obj != 'object' ) {
                         obj = JSON.parse(obj);
                      }
                      resolve(obj);
                   }else {
                      reject(requestObj);
                   }
               }
           }
       })
    }
};